I've found the marks on the shaft tube and housing, but have been unable to determine my rear ratio:

2PJ G290 1 (shaft #)

J118 (housing)
1254333 (housing)

Based on one of the previous threads written, I suspect I have 2.73 gears. I get 1.2 turns of the shaft for every rev of the tire.

Part 2 of my issue is my speedo is off 10mph. Std tire size is E78-14 and I currently have 235/70 R15's, not sure of what steps to take to get proper speedo gear.

Will gratefully take info on any of the two issues!

PJ is the code for a 2.41 non-posi rear.

Is your speedometer 10 mph off at 20mph, 50mph, or 100mph? You need to know the percentage of error to correct it. Once you know the percentage of error, simply pull the speedometer driven gear out of the tranny where the speedometer cable connects, count the teeth on it, and buy a gear that changes by that percentage. Make sure you go the right direction.

Thanx!!!!

DW

Based on one of the previous threads written, I suspect I have 2.73 gears. I get 1.2 turns of the shaft for every rev of the tire.

Part 2 of my issue is my speedo is off 10mph. Std tire size is E78-14 and I currently have 235/70 R15's, not sure of what steps to take to get proper speedo gear.

Will gratefully take info on any of the two issues!

Gary found your ratio, I'm pretty sure.

It's an open rear end... 1.2 * 2 = 2.4
Sounds like a stock 2.41 Ring/Pinion gear set.
I am assuming you have a TH350 auto tranny for the speedo calculations.

Your speedo should be accurate within a couple MPH at 60 with this combo:
20 teeth on the drive gear (brown)
34 teeth on the driven gear (light green)